Body Composition Indices of a Load-Capacity Model: Gender- And BMI-specific Reference Curves

Public Health Nutr. 2015 May;18(7):1245-54. doi: 10.1017/S1368980014001918. Epub 2014 Sep 15.


Objective: Fat mass (FM) and fat-free mass (FFM) are frequently measured to define body composition phenotypes. The load-capacity model integrates the effects of both FM and FFM to improve disease-risk prediction. We aimed to derive age-, gender- and BMI-specific reference curves of load-capacity model indices in an adult population (≥18 years).

Design: Cross-sectional study. Dual-energy X-ray absorptiometry was used to measure FM, FFM, appendicular skeletal muscle mass (ASM) and truncal fat mass (TrFM). Two metabolic load-capacity indices were calculated: ratio of FM (kg) to FFM (kg) and ratio of TrFM (kg) to ASM (kg). Age-standardised reference curves, stratified by gender and BMI (<25.0 kg/m2, 25.0-29.9 kg/m2, ≥30.0 kg/m2), were constructed using an LMS approach. Percentiles of the reference curves were 5th, 15th, 25th, 50th, 75th, 85th and 95th.

Setting: Secondary analysis of data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES).

Subjects: The population included 6580 females and 6656 males.

Results: The unweighted proportions of obesity in males and females were 25.5 % and 34.7 %, respectively. The average values of both FM:FFM and TrFM:ASM were greater in female and obese subjects. Gender and BMI influenced the shape of the association of age with FM:FFM and TrFM:ASM, as a curvilinear relationship was observed in female and obese subjects. Menopause appeared to modify the steepness of the reference curves of both indices.

Conclusions: This is a novel risk-stratification approach integrating the effects of high adiposity and low muscle mass which may be particularly useful to identify cases of sarcopenic obesity and improve disease-risk prediction.

Keywords: Appendicular skeletal mass.

Publication types

  • Comparative Study

MeSH terms

  • Absorptiometry, Photon
  • Adiposity*
  • Adult
  • Algorithms
  • Body Mass Index
  • Cohort Studies
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Models, Biological*
  • Muscle, Skeletal / diagnostic imaging*
  • Muscle, Skeletal / physiopathology
  • Nutrition Surveys
  • Obesity / diagnostic imaging*
  • Obesity / epidemiology
  • Obesity / physiopathology
  • Overweight / diagnostic imaging*
  • Overweight / epidemiology
  • Overweight / physiopathology
  • Prevalence
  • Risk Assessment
  • Sarcopenia / diagnostic imaging*
  • Sarcopenia / epidemiology
  • Sarcopenia / physiopathology
  • Sex Factors
  • United States / epidemiology
  • Weight-Bearing
  • Whole Body Imaging